As semiconductor devices have developed, there has been a move towards creating semiconductor devices with lower supply voltages, yet higher operational currents (so called low-voltage, high-current designs). In such designs, one of the significant causes of power loss/waste (i.e. power dissipated as heat, rather than contributing to the processing capability of the semiconductor) is from the so called “IR drop”.
IR drop is typically caused by the losses resultant from the resistive portion (R) of the active parts of a semiconductor's impedance interacting with the currents (I) flowing through those active portions of the semiconductor device, according to Ohms law. In actual fact, the dissipated power losses are related to the square of the current, according to the equation Power loss=I2R. Active portions of a semiconductor device may be defined by those currently enabled/powered up, and receiving a clock or other switching signal.